It’s the genius mashup that combines the taste of a savoury sandwich with the look of a cake: a sandwich cake.

This creation hails from Sweden – where it is called smörgåstårta – and is eaten at celebrations such as Midsummer, birthdays and christenings. It is also popular in Estonia, Finland and Iceland and is similar to a layered cream cake.

It also takes inspiration from afternoon tea sandwiches, and is generally made up of several layers of bread with creamy fillings in between.

Ham, roast beef and cold cuts through to caviar, vegetables, cheese, salmon and prawns all make for delicious constituents – because what doesn't go well in a sandwich?

Social media sensation

Sainsbury’s has called it out as the latest food trend. In a post on Instagram, the supermarket highlighted an eye-catching prawn and asparagus cake.

The retailer hasn’t suddenly started selling the cakes in stores. Instead, it gives the recipe for the cake, which includes ingredients like cream cheese, lemon, double cream, dill, a wholemeal country loaf, cucumber, smoked salmon and sour cream.

The asparagus is expertly deployed to surround the cake, just like the craze to edge a dessert cake with Kit Kats – a trend that hit social media feeds a few years ago.

The sandwich cake isn’t unknown either – a search on Instagram for smörgåstårta finds over 51,000 posts.

So for Sparkie’s birthday should we be getting a sandwich gateau?

Sparkie says:

The sandwich cake is an interesting idea, but I doubt it will have any more mass appeal than a standard sandwich. For those restaurants looking to offer something a little interesting, it could be a unique brunch item that could be used for social media marketing.

I really can’t see retailers taking the gamble on putting out an actual commercial product for it, even if it's Sainsbury's taking the lead, but it is very good advertisement for their range of ingredients that you can use to make it.

I would expect to see more posts like this one as the retailers finally catch up with the idea of viral social media marketing – quirky recipes using specific ingredients that you can only get in their store to put together something worthy of Instagram.